Device for arresting the elevation aiming motion of a periscope

ABSTRACT

The device is used with a periscope, associated with a remote control arrangement, for determining the line of sight. The periscope elevation aiming motion is effected by a shaft, driven by an angle drive, which is preferably a friction drive, with the shaft effecting angular adjustment of a totally reflecting component, such as a mirror, of the periscope. First and second control units are mounted on the shaft, with the first unit being a clamping nut threadedly engaged with the shaft and fixed against rotation so as to move axially of the shaft when the shaft is rotated. The second control unit is a disk fixed to the shaft to rotate therewith and having a notch in its periphery. The first control unit carries a roller. Respective detent means are cooperable with each control unit to arrest motion of the shaft in a predetermined null angular position of the mirror, and the detent means comprise elements cooperable with the roller and with the notch in the disk. The detent means are operated by an electromagnet. Upon operation of the detent means, pins engage in diametrically opposite apertures of a disk carried by a drive shaft of the angle drive so that the angle drive can no longer be operated. Alternatively, the operation of the detent means may be effected manually by a cam and cam follower arrangement having an operating knob which is releasably latched, by a detent, in the null angular position of the mirror.

United States Patent 191 Hohl et al.

1 1 Jan. 1, 1974 [73] Assignee: Messerschmitt-Bolkow-Blohm Gesellschaft mit beschrankter, H Haftung Munich, Germany [22] Filed: Feb. 12, 1973 [21] Appl. No.: 333,363

Related U.S. Application Data [63] Continuation of Ser. No. 140,126, May 4, 1971,

abandoned.

[52] U.S. Cl 350/301, 350/52, 350/22 [51] Int. Cl. G02b 5/08 [58] Field of Search "35112134,

[56] References Cited UNITED STATES PATENTS 3,409,371 11/1968 Strang 350/301 2,981,143 4/1961 Gavrisheff 350/22 3,262,364 7/1966 Kollmorgen 350/301 Primary ExaminerRonald L. Wibert Assistant ExaminerMichael J. Tokar Att0rney.l0hn J. McGlew et al.

[ 57] ABSTRACT The device is used with a periscope, associated with a remote control arrangement, for determining the line of sight. The periscope elevation aiming motion is effected by a shaft, driven by an angle drive, which is preferably a friction drive, with the shaft effecting angular adjustment of a totally reflecting component, such as a mirror, of the periscope. First and second control units are mounted on the shaft, with the first unit being a clamping nut threadedly engaged with the shaft and fixed against rotation so as to move axially of the shaft when the shaft is rotated. The second control unit is a disk fixed to the shaft to rotate therewith and having a notch in its periphery. The first control unit carries a roller. Respective detent means are cooperable with each control unit to arrest motion of the shaft in a predetermined null angular position of the mirror, and the detent means comprise elements cooperable with the roller and with the notch in the disk. The detent means are operated by an electromagnet. Upon operation of the detent means, pins engage in diametrically opposite apertures of a disk carried by a drive shaft of the angle drive so that the angle drive can no longer be operated. Alternatively, the operation of the detent means may be effected manually by a cam and cam follower arrangement having an operating knob which is releasably latched, by a detent, in the null angular position of the mirror.

10 Claims, 4 Drawing Figures PATENTEUJAN 1 1274 SHEET 1 OF 3 Fig. 1

INVENTORS mr w O m E n CA nAe PATHHEU 3,782,808

SHLU 3 Ui 3 INVENTORS.

Jean-Marie Hohl Anton Schipf Werner Schmid y x041, mt CM ATTORNEYS This is a continuation, of application Ser. No. 140,126 filed May 4, 1971, now abandoned.

BACKGROUND OF THE INVENTION In the remote control of missiles which are directed to their target by the so-called target coincidence method, the function of the guidance offlcer is to keep the missile to be guided always on the straight line connecting the eye of the guidance officer with the target to be reached by the missile. If the missile is guided from within an armoured shelter or enclosure, a periscope is used to determine the line or sight. In this case, the target coincidence line is determined by the optical axis of the periscope, with which the operator or officer must continuously follow the target, if it is moving, as to azimuth and elevation. Additionally, there is a launching device for the missile to be remotely controlled, and this launching device must be moved into the direction of the target prior to firing of the missile.

The aiming device and the follow-up device, such as the periscope, are movably arranged so that they can be moved with respect to each other in order to prevent the accuracy of the follow-up or tracking of the missile being impaired by the necessity to move too large a mass. Normally, the periscope is rigidly connected with the aiming device, such as the launching device carrying the missile, up to the launching of the missile. Both devices thus are conjointly aimed at the target, so that the axis of the launching device is parallel to the optical axis of the periscope. Accurate alignment of the periscope and the launching device is particularly necessary if the missile, right at the start of the launching, is to be held in the very small capturing range of an infrafed location-finding device cooperating with the periscope, and by which an automatic determination of the deviation of the missile from the target coincidence line, and thereby a simplification of the guidance process, is possible.

After launching of the missile, this rigid connection is disengaged and the tracking or follow-up movement of the line of sight about the vertical axis is effected by rotating the periscope, while, for aiming in elevation, a totally reflecting component provided in the periscope, such as, for example, a mirror, is angularly adjusted about a horizontal axis. The arrangement is so' designed that a ray of light arriving at the periscope through an objective lens and incident on the mirror is deflected to an arrangement of prisms, and this prism arrangement effects a splitting of that portion of the ray which is parallel to the longitudinal axis of the periscope into two partial rays which are mutually parallel and parallel to the axis of the periscope. One partial ray reaches the eyepiece of the periscope through an optical system and a reversing mirror. The other partial ray is directed to the above-mentioned infrared goniometer, which feeds a computer generating the signals required for guiding the missile.

After completion of the guided flight of a missile, the periscope consequently is displaced relative to the launching-device with respect to elevation and azimuth. For another aiming operation, in order to fire a second missile, the follow-up or tracking device therefore must again occupy exactly the initial position defined above. This applies also to the mirror which executes the elevation aiming motion in the periscope and which must be in a neutral or null position, in which null position it is secured against uncontrolled angular movement.

SUMMARY OF THE INVENTION This invention relates to means for arresting the elevation aiming motion of a periscope and, more particularly, to means for, arresting the elevation aiming motion of a periscope associated with a remote control arrangement for determining the line of sight, and in which the elevation aiming motion is effected in the periscope by means of a shaft driven by an angle drive and rotating a totally reflecting component, such as shown and described in U.S. Pat. No. 3,466,968.

The invention is based on the fact that the position, at any time, of the reflecting component in the periscope cannot be ascertained by a guidance operator within an armoured shelter or enclosure. With this in mind, the objective of the invention is to provide a device for arresting the elevation aiming motion of a totally reflecting component in a periscope, and which makes possible arresting this component, from within the armoured shelter, in a defined position, particularly in its center or null position, without play and without the necessity to observe the position of the totally reflecting component. The means are so designed that they can be operated automatically as well as manually.

In a known device for the elevation aiming motion of a mirror contained in a periscope, such as disclosed in U.S. Pat. No. 3,466,968, the shaft coupled with the tilting axis of the mirror is driven by a friction wheel drive and a manually operated control knob. The return of the mirror to the neutral or null position is effected by an electric motor which can be optionally energized, and which blocks the driven shaft connected with the mirror. In this arrangement, there exists the possibility that the control knob may be moved after the return of the mirror to its neutral position, and this leads to pronounced wear or formation of grooves in the friction wheel drive. In turn, the accuracy of the sight motion about the horizontal axis is thereby impaired.

Starting with the known arrangement, in accordance with the invention, the shaft is provided with a device cooperating with detent means for arresting motion of the shaft positively as to contact and force. The device consists of a first control unit, responding to the number of rotations of the shaft, and a second control unit which determines a defined angular position of the shaft.

The shaft is designed as a spindle, in the region of the totally reflecting component and in the region of the detent means or elements. One control unit is arranged to be adjustable as to height, or axially of the shaft, but secured against rotation, and the other control unit is secured to the spindle part of the shaft for rotation therewith but secured against displacement axially of the shaft. In addition, there are provided further locking elements blocking the angle drive, and whose transition into the blocking position can also be triggered by the control units. All detent and locking elements are arranged on a rail, or connected with the rail, and this rail is in active connection with a drive which moves it against the bias of a spring. It is desirable that the detent and locking elements, the rail and such drive are arranged in a frame designed with an approximately U-shaped cross-section, and provide an interchange able assembly.

As a further development of the concept of the invention, the height-adjustable control unit comprises a clamping plate which is secured against rotation by a pin guided in a wall of the device, and which has a roller on its end surface facing the rail, this heightadjustable control unit being formed as a nut running on the threaded lower part of the spindle. On the other hand, the rotatable control unit is a disk fixedly connected with the lower part of the spindle and formed with a self-centering keyway at its circumference. For the purpose of blocking the angle drive, the latter includes a perforated disk associated with the blocking or blocking elements.

In accordance with a further feature of the invention, the rail is formed with a recess corresponding to the roller, and is connected with a pivoted lever oriented perpendicularly to the rail, which rail carries a detent element cooperable with the keyway of the disk. One end of the rail is connected, through a pin and slot arrangement, to a plate which, in turn, is connected with a cross-piece on which the locking elements for the angle drive are arranged. In order to increase the reliability of operation of the device, the rail can be operated by an automatically controlled drive as well as manually by a lever.

The invention device thus solves, for the first time and with simple and reliable mechanical means, the problem present in the aiming apparatus disclosed in US. Pat. No. 3,466,968, which is, namely, that of arresting, in a defined position, the totally reflecting component within a periscope and from within an armoured shelter. As the arresting operation can be effected by means of an automatically controlled drive as well as manually, the periscope can serve the operator as a sighting device through the armour, in the event of a failure of the automatically operated device. In this manner, a missile leaving the launching device can be guided manually to its target, provided that, in addition to the automatic guidance device, a second and manually operable guiding device is provided. Such manually operable guiding device may be of the type shown and described, for example, in US. Pat. No. 3,224,710.

Due to the positive contact making design of the detent elements, the null position of the mirror can be determined exactly, so that deviations between the null position of the follow-up or tracking device and the null position of the launching device, such as have occurred up to now, can no longer occur. Such deviations led, as a rule, to loss of the missile from the control loop, due to the small capturing range of the infrared goniometer.

An object of the invention is to provide a device for arresting the elevation aiming motion of a periscope associated with a remote control arrangement for determining the line of sight.

Another object of the invention is to provide such a device usable with a periscope whose aiming motion is effected by a shaft, driven by an angle drive, and effecting angular adjustment of a totally reflecting component of the periscope.

A further object of the invention is to provide such a device which can be operated either manually or automatically.

Another object of the invention is to provide such a device which can be effectively used, from within an armoured enclosure, to reset a totally reflecting component of the periscope, and which is outside the armoured enclosure, back to a predetermined null or neutral position.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a perspective view, somewhat exploded, of a device for arresting the elevation aiming motion of a periscope and embodying the invention;

FIG. 2 is a top plan view, partly in section, of the means for operation of the detent means;

FIG. 3 is a somewhat schematic side elevation view, partly in section, of a periscope which is arranged with its viewing part above an armoured shelter and with its eyepiece part within the armoured shelter; and

FIG. 4 is a somewhat schematic illustration of a device for manual operation of the detent means.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the invention, and as shown in FIG. 1, there is provided, in a periscope in which the azimuth aiming motion is effected by rotation of the periscope about a vertical axis and the elevation aiming motion by rotation of a totally reflecting component, in the region of the exit aperture of the periscope, about a horizontal axis, a device 1 for arresting the elevation aiming motion of a mirror 3 as shown in FIG. 3. The device comprises a conical wheel 4 to drive a spindle 5 having a lower spindle part 6 and, in the region of the objective lens of the periscope, an upper spindle part 22 (FIG. 3). Conical wheel 4 can be driven by a shaft 7 connected to a hand-wheel, which has not been shown. A perforated disk 8 is secured to shaft 7 and serves to block drive shaft 7 in a manner which will be described in detail hereinafter. The angle drive 4 further includes a driven conical wheel 9 and, in axial succession along spindle or shaft 5 following wheel 9 there are arranged three disk springs l0, l1 and 12 which serve to take up the play and also for damping. For reasons of space, disk springs 10 and 11 are of smaller diameter than disk spring 12.

In accordance with the invention, there is arranged, above disk spring 12, a control unit 14 in the form of a disk fixed to rotate with spindle or shaft 5, this disk being formed with a conical or inwardly converging self-centering keyway 15 in its periphery. Control unit 14 is followed by a second control unit 17 in the form of a slotted clamping plate which has, at one end, a roller 19 while, at its slotted end, clamping plate 17 has a clamping screw 20 extending therethrough. Control unit 17 is connected with spindle or shaft 5 through a nut 21, so that it can move longitudinally or axially of spindle 5, thus being adjustable as to height. In order to prevent rotation of the clamping plate, a pin 23 fixed thereto is guided in a vertically extending slot 24 in the wall 18 of the housing, which housing has not been shown in detail.

An assembly 25, which contains all the detent elements of the device, cooperates with spindle or shaft 5. Assembly 25 comprises a carrier 27 which has, on its lower part, a socket-shaped lateral extension 26 which is approximately U-shaped in cross-section, and in which a part of the detent elements can reciprocate between their locking position and their disengaged position. On that side of carrier 27 facing away from spindle 5, there is mounted an electromagnet 28 which, as best seen in FIG. 2, operates, through a tappet or armature 29, a pivoted lever 30 which is fulcrumed in carrier 27 at point 32 through the medium of a guide slot 33 surrounding pivot point 32.

The free end of lever 30, opposite its fulcrum, is fixedly connected with a rail 35 (FIG. 1) oriented perpendicularly relative to lever 30 and parallel to spindle or shaft 5. The free end of lever 30, fixedly connected to rail 35, has a conical or tapered extension 36 which mates with detent recess 15 in the blocked position of the device. Above extension 36, rail 35 is formed with a recess 38 whose boundary surfaces are so shaped that roller 19, which is aligned with this recess in a definite position of the spindle for the purpose of locking, is held in the recess by a wedge action.

Upon clockwise rotation of lever 30, as viewed in FIG. 2, and against the bias of a spring 39, lever 30 engages a pin 40 secured in carrier 27 by a screw 41. For seating on pin 40, lever 30 is formed with a shallow recess 42 corresponding to pin 40. On that side of carrier 27 opposite pin 40, there is a microswitch 43 whose plunger is actuated by lever 30, upon rotation of the lever, to transfer the detent means into their effective position. Lever 30 rests, through a pin 45 secured thereto, and against the bias of a spring 46, on a pin 47 arranged in a ledge 48 of carrier 27.

The lower end of rail 35, which rail is fixed to lever 30, is supported, through a slot guide 50 and an antifriction bearing 51, in a plate 52 connected by springs 54, 55 with a movable cross-piece 66. Cross-piece 66, which is shown in FIG. 1 in its locking position, carries on both ends of the surface facing perforated disk 8 respective loose bolts 58, 59 which can be reciprocated in part 26 of carrier 27, together with cross-piece 66, and in a manner described hereinafter. Each bolt 58 and 59 is surrounded by a guide sleeve, of which only guide sleeve 60, located in front as viewed in FIG. 1, is visible in FIGS. 1 and 2. The guide sleeves are supported in respective parts of carrier 27, each of which parts is designed as a bearing block 61, 62, respectively, so that the guide sleeves can be reciprocated.

Within the bore 64 in each bearing block 61, 62, and which accommodate the guide sleeves, respective compression springs 65 are arranged. Each compression spring has one end engaging a guide sleeve contacting cross-piece 66 and the other end engaging a shoulder 67 on the respective bolts 58, 59. Upon movement of the detent elements through lever 30, rail 35 and crosspiece 56, bolts 58 and 59 are shifted, through guide sleeve and compression springs 65, to the position shown in dash-dotted lines in FIG. 2 and until shoulders 67 strike the ends of bores 64. In this position, bolts 58 and 59 can engage in diametrically opposite holes or apertures of perforated disk 8 and, in this manner, block rotation of drive shaft 7 of spindle or shaft 5. Should bolts 58, 59, in their extreme extended position, strike disk 8 between apertures therein, compression springs are tensioned. In this case, a slight rotation of shaft 7, by hand, is sufficient to bring about coincidence of the apertures and the bolts, and thereby effect positive blocking. I

The described device for arresting the elevation aiming motion of a mirror in a periscope is arranged in the lower region of a sighting assembly 87 which also carries eyepiece 88 of the periscope. This sighting assembly is located, as best seen in FIG. 3, below a cover 90, for example, an armour plate. Spindle 5 is extended beyond the aperture 91 of the periscope and is connected, through spindle part 22 and a sector gear 93, with mirror 3 for the purpose of angularly adjusting the latter about a horizontal axis.

The operation of the device will now be described. The desired null position of mirror 3 has been determined, during assembly in the periscope, by adjusting nut 21 on spindle 5. In order to be able to carry out a sensitive elevation alignment, five rotations, in either direction of rotation, of shaft 5 are possible from this null point. After a completed or interrupted follow-up or tracking operation, magnet 28 is energized by switching means controlled by the guidance equipment, and attempts to move rail 35 downwardly, as viewed in FIG. 2, through lever 30. By turning the hand wheel in either direction, the guidance operator now brings mirror 3 into the required null position in which the optical axis of the periscope is parallel to the axis of the launching device, so that the periscope therefore occupies its initial position for a new aiming operation. In this null position of mirror 3, control units 14 and 17 are aligned with detent elements 36 and 38, respectively, in a manner such that automatic locking takes place. In this position, roller 19 is opposite recess 38 and peripheral notch or recess 15 of control unit 14 is opposite extension 36 of lever 30, so that the excited magnet 28 transfers the latter into their detent position. At the same time, pins 58, 59 engage respective apertures in perforated disk 8. Thereby, driven shaft 7 is also blocked and it is prevented that, in the event of uncontrollable rotation of the hand wheel, wear of the conical friction wheels takes place, and which wear would impair the fine adjustment of the device. Release of the arresting action is effected by compression spring 46 as soon as electro-magnet 28 is deenergized.

In place of automatic actuation of the device, manual operation can be provided, as shown in FIG. 4. In this case, lever 30' is given an angular shape and has an offset 70 formed in such a manner that the free end 71 of the lever is in active engagement with the cylindrical rotatable part 75 through a roller 74. Cylindrical part 75 has a contact surface 77 of a predetermined pitch, so that extension 36 of lever 30 engages keyway 15 as soon as lever 30' is at the lowest point of this contact surface. Part 75 is in a receptacle 78 which is then formed as a shaft 81 connected with a control knob 80.

Shaft 81 is supported in a bearing part 82. Controlknob has a square recess receiving a square end 85 of shaft 78, and a spring biased ball detent 86 is cooperable with control knob 80 to arrest the latter in the predetermined zero or null position after one rotation through 360.

The operation of the device shown in FIG. 4 is analogous to that described with respect to FIGS. 1, 2 and 3. Of course, both the manually operable device and the automatically operable device can be combined with each other.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

We claim:

1. in a remote control arrangement for missile guidance, including a periscope determining the line of sight for guiding a missile, launched from a launching device having a launching axis, to its target, with the periscope elevation aiming motion being effected by a shaft, driven by an angle drive, effecting angular adjustment of a totally reflecting component of the periscope, a device for arresting, in a predetermined null angular position of said totally reflecting component, in which the optical axis of the periscope is at least parallel to the launching axis of the launching device, the elevation aiming movement of the periscope, said device comprising, in combination, first and second control units mounted on said shaft, one responding to the number of rotations of said shaft and the other responding to the angular position of said shaft; and respective selectively operable releasable detent means cooperable with said control units to arrest motion of said shaft, positively as to contact and force, only in said predetermined null angular position of said totally reflecting component during launching of the missile; whereby, after release of said detent means following launching of the missile, the elevation aiming movement of the periscope may be operated to adjust the optical axis of the periscope angularly in both a positive and a negative direction from said null angular position to guide the missile to its target.

2. A device as claimed in claim 1, in which said shaft is designed as a spindle in the vicinity of said detent means; said first control unit being arranged on the spindle part of the shaft for movement axially of the shaft, responsive to rotation of the shaft, but fixed against rotation; said second control unit being fixed to said shaft for rotation therewith and against displacement axially of said shaft.

3. A device as claimed in claim 1, including further locking elements selectively movable to a locking position to engage and lock said angle drive against movement; the movement of said further locking elements into the angle drive locking position being initiated by said control units.

4. A device as claimed in claim 1, including a rail operatively associated with said detent means and said further locking elements; spring means biasing said rail to a position retracting said detent means and said further locking elements to the retracted position; and a selectively operable drive operatively associated with said rail and operable to move said rail in a direction moving said detent means and said further locking elements to the locking position.

5. A device as claimed in claim 4, in which said shaft is designed as a spindle in the vicinity of said detent means; said first control unit being mounted on the spindle part of said shaft for movement vertically axially of said shaft while secured against rotation; said second control unit being secured to said shaft for rotation therewith and against axial displacement along said shaft; said first control unit comprising a clamping plate restrained against rotation by a pin thereon guided in a wall of said device; a roller on an end surface of said clamping plate facing said rail; and a nut on said clamping plate threadedly engaged with said spindle part of said shaft.

6. A device as claimed in claim 2, in which said second control unit is a disk fixedly connected with a lower portion of said shaft designed as a spindle; said disk being formed with a self-centering keyway at its periphery.

7. A device as claimed in claim 3, in which said angle drive includes a perforated disk rotatable therewith and operatively associated with said further locking elements.

8. A device as claimed in claim 5, in which said rail is formed with a recess aligned with said roller; a hinged lever perpendicular to said rail and connected thereto; said second control unit comprising a disk fixedly connected with a lower portion of said shaft formed as a spindle, said disk being formed with a self-centering keyway at its periphery; a detent element carried by said lever and aligned with said keyway; a movable plate; a cross-piece connected to said plate; locking elements on said cross-piece engageable with said angle drive to lock the same against rotation; one end of said rail carrying a pin engaged in a slot in said plate to move said plate upon movement of said rail into a locking position.

9. A device as claimed in claim 8, including a manually operable cam; said lever being engageable with said cam for movement thereby.

10. A device as claimed in claim 4, in which said drive comprises a selectively energizable electromagnet having a movable armature operatively associated with said rail. 

1. In a remote control arrangement for missile guidance, including a periscope determining the line of sight for guiding a missile, launched from a launching device having a launching axis, to its target, with the periscope elevation aiming motion being effected by a shaft, driven by an angle drive, effecting angular adjustment of a totally reflecting component of the periscope, a device for arresting, in a predetermined null angular position of said totally reflecting component, in which the optical axis of the periscope is at least parallel to the launching axis of the launching device, the elevation aiming movement of the periscope, said device comprising, in combination, first and second control units mounted on said shaft, one responding to the number of rotations of said shaft and the other responding to the angular position of said shaft; and respective selectively operable releasable detent means cooperable with said control units to arrest motion of said shaft, positively as to contact and force, only in said predetermined null angular position of said totally reflecting component during launching of the missile; wherEby, after release of said detent means following launching of the missile, the elevation aiming movement of the periscope may be operated to adjust the optical axis of the periscope angularly in both a positive and a negative direction from said null angular position to guide the missile to its target.
 2. A device as claimed in claim 1, in which said shaft is designed as a spindle in the vicinity of said detent means; said first control unit being arranged on the spindle part of the shaft for movement axially of the shaft, responsive to rotation of the shaft, but fixed against rotation; said second control unit being fixed to said shaft for rotation therewith and against displacement axially of said shaft.
 3. A device as claimed in claim 1, including further locking elements selectively movable to a locking position to engage and lock said angle drive against movement; the movement of said further locking elements into the angle drive locking position being initiated by said control units.
 4. A device as claimed in claim 1, including a rail operatively associated with said detent means and said further locking elements; spring means biasing said rail to a position retracting said detent means and said further locking elements to the retracted position; and a selectively operable drive operatively associated with said rail and operable to move said rail in a direction moving said detent means and said further locking elements to the locking position.
 5. A device as claimed in claim 4, in which said shaft is designed as a spindle in the vicinity of said detent means; said first control unit being mounted on the spindle part of said shaft for movement vertically axially of said shaft while secured against rotation; said second control unit being secured to said shaft for rotation therewith and against axial displacement along said shaft; said first control unit comprising a clamping plate restrained against rotation by a pin thereon guided in a wall of said device; a roller on an end surface of said clamping plate facing said rail; and a nut on said clamping plate threadedly engaged with said spindle part of said shaft.
 6. A device as claimed in claim 2, in which said second control unit is a disk fixedly connected with a lower portion of said shaft designed as a spindle; said disk being formed with a self-centering keyway at its periphery.
 7. A device as claimed in claim 3, in which said angle drive includes a perforated disk rotatable therewith and operatively associated with said further locking elements.
 8. A device as claimed in claim 5, in which said rail is formed with a recess aligned with said roller; a hinged lever perpendicular to said rail and connected thereto; said second control unit comprising a disk fixedly connected with a lower portion of said shaft formed as a spindle, said disk being formed with a self-centering keyway at its periphery; a detent element carried by said lever and aligned with said keyway; a movable plate; a cross-piece connected to said plate; locking elements on said cross-piece engageable with said angle drive to lock the same against rotation; one end of said rail carrying a pin engaged in a slot in said plate to move said plate upon movement of said rail into a locking position.
 9. A device as claimed in claim 8, including a manually operable cam; said lever being engageable with said cam for movement thereby.
 10. A device as claimed in claim 4, in which said drive comprises a selectively energizable electromagnet having a movable armature operatively associated with said rail. 